by Todde MacDonnell

Priests were supported by the donation of stipends and expected to recite masses at all hours of the night. Which hours, you ask?
The church celebrated eight masses in the day, and laymen often recorded time by their precedent.

Matins: midnight
Lauds: 3 a.m.
Prime: 6 a.m.
Tierce: 9 a.m.
Sext: noon
None: 3 p.m.
Vespers: 6 p.m.
Compline: 9 p.m.

Peasants were notorious for sleeping through the Sunday Prime mass and when they didn’t, invariably slept through the sermon.

Source: Life in a Medieval City, Joseph and Frances Gies Sleep disorder hypothesis is entirely my fault.